1. Field of the Invention
The present invention relates to disk drives. More particularly, the present invention relates to air-bearing sliders that include a textured air-bearing surface (ABS) and to head stack assemblies and disk drives that include such an air-bearing slider.
2. Description of the Prior Art
A typical hard disk drive includes a head disk assembly (“HDA”) and a printed circuit board assembly (“PCBA”). The HDA includes at least one magnetic disk (“disk”), a spindle motor for rotating the disk, and a head stack assembly (“HSA”) that includes a slider with at least one transducer or read/write element for reading and writing data. The HSA is controllably positioned by a servo system in order to read or write information from or to particular tracks on the disk. The typical HSA has three primary portions: (1) an actuator assembly that moves in response to the servo control system; (2) a head gimbal assembly (“HGA”) that extends from the actuator assembly and biases the slider toward the disk; and (3) a flex cable assembly that provides an electrical interconnect with minimal constraint on movement.
A typical HGA includes a load beam, a gimbal attached to an end of the load beam, and a slider attached to the gimbal. The load beam has a spring function that provides a “gram load” biasing force and a hinge function that permits the slider to follow the surface contour of the spinning disk. The load beam has an actuator end that connects to the actuator arm and a gimbal end that connects to the gimbal that supports the slider and transmits the gram load biasing force to the slider to “load” the slider against the disk. A rapidly spinning disk develops a laminar airflow above its surface that lifts the slider away from the disk in opposition to the gram load biasing force. The slider is said to be “flying” over the disk when in this state.
Padded sliders have been extensively used to improve the stiction problem (the tendency of facing and contacting highly polished flat surfaces to stick to one another) at the interface between the head and the disk during drive operation. FIG. 1A is a perspective view of a conventional padded slider 100. FIG. 1B is a cross-sectional view of the padded slider 100 of FIG. 1A, taken along cross-sectional line AA′. Considering now FIGS. 1A and 1B collectively, the padded slider 100 may be formed of a block of aluminum titanium carbide. The slider 100 includes an Air Bearing Surface (hereafter, ABS) 102. A shallow etch surface 114 is etched from the ABS 102 toward the leading edge of the padded slider 100. A deep etch surface 110 is etched from the ABS 102. A center pad 108 to which the slider's read/write transducer is attached is disposed on the trailing edge of the padded slider 100. As shown, the shallow etch surface 114 is disposed between the ABS 102 and the deep etch surface 110. The conventional padded slider 100 also includes a plurality of protuberances 106 that protrude from the ABS 102. The protuberances 106 are pads that are configured to minimize the stiction between the surface of the disk and the slider 100. The plurality of protuberances 106 rise away from the ABS 102 such that their free end is further away from both the shallow etch surface 114 and the deep etch surface 110 than is the ABS 102. The conventional padded slider 100, therefore, has a topology that defines at least four discrete levels: an ABS 102, protuberances 106, a shallow etch surface 114 and a deep etch surface 110. The protuberances 106 are typically formed by a separate carbon deposition process that forms the pillar-shaped structures 106. As most easily seen in FIG. 1B, the free ends of protuberances 106 of a conventional padded slider 100 may collectively form a slight radius of curvature 112, which is exaggerated in FIG. 1B for clarity of illustration.
Such conventional padded sliders have a number of disadvantages, including the separate process step required to form the plurality of protuberances 106, some limitations on the placement of such discretely-deposited protuberances and the high flying pitch of the slider. The high flying pitch of the conventional slider 100 is of particular concern, as it significantly degrades the flying performance of the head, including poor Take Off Velocity (TOV) and contributes to poor vertical pitch and roll stiffness, poor flyability and like disadvantages.
What are needed, therefore, are sliders that do not suffer from the high flying pitch disadvantages inherent in conventional padded sliders and that do not require an extra process step to deposit the stiction minimizing protuberances 106. What are also needed are head stack assemblies and disk drives incorporating such improved sliders.